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Question
Simplify:
\[\frac{x^2 - 5x - 24}{\left( x + 3 \right)\left( x + 8 \right)} \times \frac{x^2 - 64}{\left( x - 8 \right)^2}\]
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Solution
It is known that,
a2 − b2 = (a + b) (a − b)
a3 − b3 = (a − b)(a2 + ab + b2)
\[\ \frac{x^2 - 5x - 24}{\left( x + 3 \right)\left( x + 8 \right)} \times \frac{x^2 - 64}{\left( x - 8 \right)^2}\]
\[ = \frac{x^2 - 8x + 3x - 24}{\left( x + 3 \right)\left( x + 8 \right)} \times \frac{\left( x \right)^2 - \left( 8 \right)^2}{\left( x - 8 \right)^2}\]
\[ = \frac{x\left( x - 8 \right) + 3\left( x - 8 \right)}{\left( x + 3 \right)\left( x + 8 \right)} \times \frac{\left( x + 8 \right)\left( x - 8 \right)}{\left( x - 8 \right)\left( x - 8 \right)}\]
\[ = \frac{\left( x + 3 \right)\left( x - 8 \right)}{\left( x + 3 \right)\left( x + 8 \right)} \times \frac{\left( x + 8 \right)\left( x - 8 \right)}{\left( x - 8 \right)\left( x - 8 \right)}\]
= 1
RELATED QUESTIONS
Simplify:
\[\frac{8 x^3 - 27 y^3}{4 x^2 - 9 y^2}\]
Simplify:
\[\frac{4 x^2 - 11x + 6}{16 x^2 - 9}\]
Factorise:
x3 − 64y3
Factorise:
125y3 − 1
Factorise:
8p3 −\[\frac{27}{p^3}\]
Factorise:
343a3 − 512b3
Simplify:
(3xy − 2ab)3 − (3xy + 2ab)3
Factorise: x3 - 8y3
Factorise: 27p3 - 125q3.
Factorise the following:
27x3 – 8y3
